Note on the preference of aliphatic epoxides for the N-7 position of guanine in DNA.
The reactivity of aliphatic epoxides like ethylene oxide, chloroethylene oxide or propylene oxide towards N-3 and N-7 in both purine bases was calculated by the MNDO method and correlated with their HOMO coefficients. A greater chemical susceptibility of the N-3 position in both purines to aliphatic epoxides when compared with the N-7 position was found. On this background the preference of aliphatic epoxides for the N-7 position of guanine in DNA was explained by the existence of intramolecular hydrogen bonds in adenine and guanine and the steric orientation of the N-3 (minor groove) and N-7 (major groove) positions of both purines in alpha-helical DNA.
Peter
H
H
Institut für Arbeitsphysiologie, Universität Dortmund, Federal Republic of Germany.
Csanády
G
G
D000225:Adenine / Q000378:metabolism; D000477:Alkylating Agents; D000478:Alkylation; D004247:DNA / Q000187:drug effects / Q000378:metabolism*; D004852:Epoxy Compounds / Q000633:toxicity*; D005027:Ethylene Oxide / Q000031:analogs & derivatives / Q000633:toxicity; D006147:Guanine / Q000378:metabolism*; D006860:Hydrogen Bonding
D000477:Alkylating Agents; D004852:Epoxy Compounds; D006147:Guanine; C015061:chloroethylene oxide; D004247:DNA; D000225:Adenine; D005027:Ethylene Oxide; C009068:propylene oxide